Electron microprobe analysis has been employed to examine the phosphorus and divalent cations in the storage granules in bacteria and in platelets of cows with storage pool deficiency. Mass thickness measurements with a scanning-transmission electron microscope have confirmed the localization of iodinated quinacrine in platelet dense bodies, and should prove useful in the subcellular localization of other iodinated tracers as well. Contact x-ray microscopy of dried specimens has revealed novel structure in platelets, nervous tissue, and bacteria, and flash x-ray microscopy of hydrated specimens has been accomplished. Preliminary work indicates that x-ray holography of similar specimens will be possible.